Keryx shares keep climbing on drug trial results

Shares of Keryx Biopharmaceuticals Inc. extended its gains Tuesday, a day after the drug developer said its potential kidney disease drug, Zerenex, performed much better than a placebo in a late-stage clinical trial.

THE SPARK: The New York company said Monday that Zerenex showed a "highly statistically significant" change in serum phosphorus levels compared with a placebo in patients with advanced kidney failure who were on dialysis.

The drug also improved iron levels in patients, reducing the use of intravenous iron and other agents designed to treat anemia by boosting the oxygen-carrying component of the blood. The company said that should separate Zerenex from similar treatments on the market.

THE BIG PICTURE: Keryx has no products on the market, and Zerenex is its most advanced drug. The company plans to submit an application for approval of the drug to both the U.S. Food and Drug Administration and European regulators in this year's second quarter.

THE ANALYSIS: The magnitude of how much Zerenex decreases the need for the intravenous treatments was much better than expected, Stifel Nicolaus analyst Stephen Willey said in a research note. His estimate for peak, annual sales of the drug more than doubled to a range of $550 million to $600 million.

SHARE ACTION: Up 41 percent, or $2.48, to $8.54 in afternoon trading. The stock rose as high as $8.71 earlier in the session, its highest level since May 2010. It had soared 77 percent on Monday after Keryx announced the study results. The share price has more than tripled since the start of the year.